Vehicle mounted radio antennas are generally known for receiving radio broadcast signals and for two-way communication in mobile telephone applications. Vehicle mounted antenna are also known for voice communications in military applications.
In static applications, a known antenna assembly comprises an antenna array comprising several vertically stacked dipole antennas each of which operates over the same frequency band. In transmission mode, each antenna is fed the same carrier frequency signal with the signal fed to the upper and lower antennas being phase shifted relative to middle antenna to increase the concentration of electromagnetic energy in the horizontal direction.